Carbon burner



J n 2 1957 F. J. SULLIVAN ET AL 2,797,081

CARBON BURNER Filed Feb. 7. 1949 IN VEN TORS Jus tin h. Al/en Edward J 5BY Francis J \su/flvan CARBON BURNER Francis J. Sullivan, Detroit, Mich,Edward J. Bair, Seattle, Wash., and Justin H. Allen, Topeka, Kans.,assignors, by direct and mesne assignments, to the United States ofAmerica as represented by the United States Atomic Energy CommissionApplication February 7, 1949, Serial No. 75,066

Claims. (Cl. 266-19) Our invention relates to combustion equipment andmore particularly to an apparatus and system for the separation andrecovery of uranium or other elements which produce non-volatile oxides,from carbon and the like.

In the separation of uranium isotopes by the electromagnetic process,for instance, the uranium is collected in carbon receivers or pockets,where it embeds itself in the carbon. In order to recover uranium, orother element or elements, the carbon is burned or ignited and theuranium or other element or elements in the form of an oxide or oxidesin the ash residue may be extracted by the application of nitric acid toform a nitrate or nitrates of elements to be recovered. In order tocarry out this 7 process, provision must be made for the separation ofany uranium or other desired element from the gases of combustion.Provision must also be made for controlling the combustion temperaturesand for conducting away the heat of combustion so that the retort orinclosure will not burn out or be consumed. In the prior art manydiflerent types of burners for this purpose have been tried. However,most of them were complicated, employed hopper feeds, oxygen jets, andcooling jackets, but very little filtering apparatus was provided forremoving entrained uranium or other desired element in the gases ofcombustion.

Applicants, with a knowledge of these defects in and objections to theprior art, have for an object of their invention the provision of aburner for quantitatively burning highly enriched carbon on a productionscale.

Applicants have as another object of their invention the provision of aburner whose heat of combustion may be carefully regulated.

Applicants have as another object of their invention the provision of aburner having a simple and compact arrangement for absorbing andconducting away the heat of combustion so that it may not be injuriousto the equipment.

Applicants have as a further object of their invention the provision ofa burner with a filtering arrangement for the complete removal ofentrained uranium or other element from the gases of combustion.

Applicants have as a still further object of their invention theprovision of a burner which may be quickly and easily charged withmaterial and from which the ash may be separated and easily removed.

Other objects and advantages of our invention will appear from thefollowing specification and accompanying drawing, and the novel featuresthereof will be particularly pointed out in the annexed claims.

The sole figure shows a front elevation, partly in section, of ourimproved burner.

Referring to the drawing in detail, 1 designates a vertical cylinder ofnickel or other appropriate material having a flange 17 on its upper endfor cooperation with a mating flange 18 on a cover 2 which is of conicalconfiguration. The two flanges are frictionally maintained in sealedabutting relation by a series of resilient clips 19, 19 carried by thecover 2 and adapted to extend over the edges of the flanges at aseriesof spaced positions along the circumference. Extending upwardly atan angle from the cover 2 is a tubular extension 20 which is externallyscrew threaded to engage a threaded cap 10 for maintaining it inposition. The cap 10 acts as a closure and carries a glass sight, orwindow, in its upper end to permit visual examination of the contents ofthe burner during combustion. Oxygen or air is supplied to the burnerthrough a tubular extension 3 which enters the apex of the conical cover2.

Cylinder 1 is closed at its lower end by an inverted conical shell 4 ofnickel or other appropriate material. This shell serves as a base forthe burner. Joined to the lower end of the shell 4 at the apex andprojecting downward therefrom is an extension 5 of nickel or otherappropriate material, externally screw threaded at its lower end forcooperation with the internal screw threads of cap 6. Cap 6 is removableso that the burner can be rinsed out quantitatively. Positioned in thelower end of cylinder 1 and resting upon the cone 4 at the juncture ofthe base or cone 4 with the cylinder 1 is a grate 11 made of a carbondisk containing a series of spaced holes. The grate is adapted toreceive and support the pieces of carbon to be burned. Joined integrallyand opening into cone or base 4 with an axis at about 60 from thevertical is cone 7 whose upper end merges into a cylindrical section 9.The upper end of the cylindrical section 9 terminates in a flangedportion 21 for cooperation with a mating flanged portion or flange 22 onconical cover 15. Spring fingers or clips 23 carried by cover 15 andspaced about the circumference of flange 22 at convenient intervalsengage over the edges of the abutting flanges 21, 22, to retain thecover 15 on the cylindrical section 9 in tight sealed relation. Thecover 15 mounts a nipple or an-enlargement defining a socket at itsapex, and this nipple or socket serves as an outlet for connection tothe manifold of a Cottrell or other electrostatic precipitator.Positioned in the cylindrical section 9 is a perforated bafile 12 havingconverging arms 13, 14 extending downwardly therefrom for engagementwith the tapering inner walls of the conical portion 7 for supportingthe bafile in an intermediate position within the cylindrical section 9.Packed in the upper part of the cylindrical section 9 and resting on theperforated baflle 12 is a barrel 16 of glass wool to provide filteringaction for the removal of entrained uranium or other element or elementsfrom the gases of combustion as they pass on out to the Cottrellprecipitator.

Above the glass wool and closing the upper end of the cylindricalsection 9 is a glass cloth filter 8. This filter is preferably supportedby having its circumferential portions clamped between the flanges 21and 22.

Wrapped, preferably in spiral form, about the outer surfaces of theportions of the burner is copper or other appropriate tubing 26 throughwhich water or other cooling media may be passed to cool the walls ofthe burner by heat transfer. The rigidity of the structure may beincreased by bridging the cylindrical portions 1, 9, with braces orcross members 27, having their end portions Welded or otherwise securedto the cylindrical sections of the burner.

In the operation of the burner, it is first cleaned thoroughly. Bafile12, glass wool barrel 16, filter cloth 8, and grate 11 are placed inposition. Cover 15 is clamped over open end of cylindrical section 9,and drain cap 6 is screwed up tight. The carbon to be burned is thenbroken into pieces approximately 2 inches square and placed in thecylindrical section 1 of the burner. The cooling water is then turned onand the carbon is ignited by lighting a wad of filter paper and closingthe lid, oxygen being supplied through line 3. As the gases resultingfrom combustion expand into the large cross section of cone 7 andcylindrical section 9, any ash carried by the slow escaping gases isfiltered out by the glass wool barrel 16 and filter cloth 8.Furthermore, the resistance of the glass Wool packing in section 9maintains the oxygen-carbon monoxide ratio above the explosive limit ofthe burner.

After combustion is completed, lid 2 is removedand carbon grate 11 istaken out to be used in the next batch. Filter cloth 8 and glass woolbarrel 16 are carefully removed and after drain cap 6 is unscrewed, theinside of the burner is thoroughly Washed down with .water or leachedwith nitric acid and the wash is received in a beaker placed, under thedrain. This leachingaction producesa solution of a nitrate or nitratesof the elements to be recovered. An element, such as uranium, may berecovered from this solution by various methods including solventextraction, evaporation, precipitation or other common methods; Forexample, in the case of uranium, a salting out agent such as coppernitrate may be added, and the resulting solution may then be extractedwith an ether, such as diethyl-ether.

Having thus described our invention, we claim:

1. A burner of the character described comprising an elongatedcombustion chamber, a grate positioned in said combustion chamber nearits lower extremity to support a charge of material, means for feedingoxygen into the upper extremity of the combustion chamber to supportcombustion of the charge, a gas expansion chamber having its lowerextremity in communication with the combustion chamber below the grate,means for removing gases of combustion from the expansion chamber, and afilter positioned in the upper extremity of the expansion chamber forremoving entrained particles of charge material from the gases ofcombustion.

2. A carbon burner of the character described comprising an elongatedbody defining a combustion chamber, a removable cover for the upper endof the body to permit insertion of a carbon charge, a grate positionedin the lower extremity of the body for supporting the charge, a ductextending into the cover for feeding oxygen into the combustion chamber,a gas expansion chamber for communication with the combustion chamber ata position beneath the grate, and a filter positioned in the expansionchamber for removing entrained particles of charge material from thegases of combustion.

3. A carbon burner of the character described comprising an elongatedsubstantially cylindrical body dc fining a combustion chamber, aremovable cover for the body to permit insertion of a carbon charge, aline leading through the cover and into said combustion chamber forsupplying oxygen, a grate positioned in the lower portion of thecombustion chamber for supporting the charge, a gas expansion chamberfor communication with the combustion chamber at a position beneath thegrate for the passage of the gases of combustion, and a glass woolfilter disposed Within the expansion chamber for removing entrainedparticles of charge material from the gases of combustion.

4. A carbon burner of the character described comprising an elongatedtubular body portion defining a combustion chamber, said body portionterminating at its lower end in a conical portion for collecting residuefrom the combustion chamber, a cover for the upper end of said bodyportion to permit the insertion of a carbon charge, means for feedingoxygen into said combustion chamber through said cover, a gratepositioned in the lower part of said chamber for supporting the charge,an expansion chamber for communication with the combustion chamberbeneath said grate for the passage of gases of combustion, and aplurality of filters disposed within the expansion chamber for theremoval of entrained particles in the combustion gases.

5. A carbon burner of the character described comprising an elongatedtubular body portion defining a combustion chamber, said body portionterminating at its lower end in a frusto conical portion, a cover forthe upper end of said body portion to permit the insertion of a carboncharge, means for feeding oxygen into said combustion chamber throughsaid cover, a grate positioned in the lower part of said chamber forsupporting the charge, a removable cap on a frusto conical portion forremoving residue from the chamber, an expansion chamber forcommunication with the combustion chamber beneath said grate for thepassage of gases of combustion, a plurality of filters disposed withinthe expansion chamber for, the removal of entrained particles in thecombustion gases, and cooling tubes disposed about the tubular body tolimit the rise in temperature thereof.

References Cited in the file of this patent UNITED STATES PATENTS 3,853Bradley Oct. 12, 1844 154,173 Hauberg Aug. 18, 1874 310,920 Spear et a1.Ian. 20, 1885 584,344 Geradin et a1. June 15, 1897 1,076,942 BackmireOct. 28, 1913 1,961,424 Maier June 5, 1934 2,247,334 Keemle June 24,1941 FOREIGN PATENTS 2,086 Great Britain Jan. 28, 1903 4,667 GreatBritain Feb. 25, 1909

1. A BURNER OF THE CHARACTER DESCRIBED COMPRISING AN ELONGATEDCOMBUSTION CHAMBER, A GRATE POSITION IN SAID COMBUSTION CHAMBER NEAR ITSLOWER EXTREMITY TO SUPPORT A CHARGE OF MATERIAL, MEANS FOR FEEDINGOXYGEN INTO THE UPPER EXTREMITY OF THE COMBUSTION CHAMBER TO SUPPORTCOMBUSTION OF THE CHARGE, A GAS EXPANSION CHAMBER HAVING ITS LOWEREXTREMITY IN COMMUNICATION WITH THE COMBUSTION CHAMBER BELOW THE GRATE,MEANS FOR REMOVING GASES OF COMBUSTION FROM THE EXPANSION CHAMBER, AND AFILTER POSITIONED IN THE UPPER EXTREMITY OF THE EXPANSION CHAMBER FORREMOVING ENTRAINED PARTICLES OF CHARGE MATERIAL FROM THE GASES OFCOMBUSTION.